/*
 * Copyright (c) 1999, 2005, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package com.xunmall.base.dto;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

/**
 * @Author: WangYanjing
 * @Date: 2018/12/27 10:53
 * @Description:
 */
@Data
@JsonIgnoreProperties(ignoreUnknown = true)
public class Pair<A, B> {

    @JsonProperty("fst")
    public A fst;

    @JsonProperty("snd")
    public B snd;

    public Pair(@JsonProperty("fst") A fst, @JsonProperty("snd") B snd) {
        this.fst = fst;
        this.snd = snd;
    }

    @Override
    public String toString() {
        return "Pair[" + fst + "," + snd + "]";
    }

    private static boolean equals(Object x, Object y) {
        return (x == null && y == null) || (x != null && x.equals(y));
    }

    @Override
    public boolean equals(Object other) {
        return
                other instanceof Pair &&
                        equals(fst, ((Pair<?, ?>) other).fst) &&
                        equals(snd, ((Pair<?, ?>) other).snd);
    }

    @Override
    public int hashCode() {
        if (fst == null) {
            return (snd == null) ? 0 : snd.hashCode() + 1;
        } else if (snd == null) {
            return fst.hashCode() + 2;
        } else {
            return fst.hashCode() * 17 + snd.hashCode();
        }
    }

    public static <A, B> Pair<A, B> of(A a, B b) {
        return new Pair<A, B>(a, b);
    }
}
